Copper Sulfate – Saline Etch for Aluminum – Test 8: Citric Acid Degeneration Test

Name: Nick Osetek & Tessa Chambers                                                 Date: 4/24/2018

Room Temperture: 65*F                                                                         Humidity etc: Dry

Experiment Title: Citric Acid Degeneration Test

Experiment Goal: We separated our original spent saline sulfate bath into 4 containers. Each container held 12 oz of the bath. We added varying amounts of citric acid to 3 of the containers to see how quickly and efficiently it would regenerate the baths. We found the citric acid brought the greenish spent colour of the bath back to its pure blue (as if the bath was new.)

Bath 1: 12 oz copper sulfate saline bath

Bath 2: 12 oz copper sulfate saline bath, 1 tsp citric acid

Bath 3: 12 oz copper sulfate saline, 1 tbsp citric acid

Bath 4: 12 oz copper sulfate saline, 1 tbsp citric acid

Our goal was to use Bath 4 for etching six 3 minute plates to test the results of the new citric acid mixture and see if we can wear it out. Then compare the results to the 3 minute etchings from the regular copper sulfate saline mixture.

Plate material: Aluminum (5052)

Plate Preparation: Degreased with Bon Ami and soy sauce, backed with contact paper

Evaluation of Plate Preparation: We forgot to buff with steel wool

Etching Bath Notes: Bath 4 looks like new with its original bright blue colour. We perviously etched a 3 minute plate in this bath already.

Time in bath: 18 minutes total in 3-minute increments

After Bath Evaluation: Bath 4 has a slight odor when etching and is much hotter. The bath was steaming when etching and the plate came out noticeably warm which didn’t happen in our original copper sulfate saline bath. The pH level seems to lower when the reader is over the plate, when you move it away the pH goes back up and becomes less acidic.

Removal of Grounds: N/A

Inking Methods: Bone black oil-based etching ink, 10% 00 burnt plate oil

Paper Type: Hahnemuhle Copperplate

Soaking Time: 1 Hour

Press, blanket set up, pressure: Praga, 2 blankets, 4/9-left 4/8-right

Conclusions: Each 3-minute test was fairly inconsistent. Plates 1 and 2 seem to be a tad lighter and spottier than plate 3 which is much blacker. Plates 4 and 5 are consistent in lightness and texture with the first 2 plates. While plate 6 turned out the lightest.

At this point in our research we encountered a ton of questions that we didn’t have the proper knowledge to answer. To answer these crucial questions we contacted Dr. Richard Peltier Associate Professor of Environmental Health Sciences at UMass Amherst. He helped us absorb the knowledge we needed to continue forward with our research.

Here are our questions and his answers:

Chemistry Questions April 19, 2018

4th 12 oz sample bath. 1 tbs citric added and etched 3 minutes. The addition of citric interrupted the oxidation process (copper stayed red).

3-minute plate comparisons. Plates 1-6.

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